KVM: x86: Clear apic tsc-deadline after deadline
[sfrench/cifs-2.6.git] / virt / kvm / async_pf.c
1 /*
2  * kvm asynchronous fault support
3  *
4  * Copyright 2010 Red Hat, Inc.
5  *
6  * Author:
7  *      Gleb Natapov <gleb@redhat.com>
8  *
9  * This file is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License
11  * as published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software Foundation,
20  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
21  */
22
23 #include <linux/kvm_host.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/mmu_context.h>
27
28 #include "async_pf.h"
29 #include <trace/events/kvm.h>
30
31 static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu,
32                                                struct kvm_async_pf *work)
33 {
34 #ifdef CONFIG_KVM_ASYNC_PF_SYNC
35         kvm_arch_async_page_present(vcpu, work);
36 #endif
37 }
38 static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu,
39                                                 struct kvm_async_pf *work)
40 {
41 #ifndef CONFIG_KVM_ASYNC_PF_SYNC
42         kvm_arch_async_page_present(vcpu, work);
43 #endif
44 }
45
46 static struct kmem_cache *async_pf_cache;
47
48 int kvm_async_pf_init(void)
49 {
50         async_pf_cache = KMEM_CACHE(kvm_async_pf, 0);
51
52         if (!async_pf_cache)
53                 return -ENOMEM;
54
55         return 0;
56 }
57
58 void kvm_async_pf_deinit(void)
59 {
60         if (async_pf_cache)
61                 kmem_cache_destroy(async_pf_cache);
62         async_pf_cache = NULL;
63 }
64
65 void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
66 {
67         INIT_LIST_HEAD(&vcpu->async_pf.done);
68         INIT_LIST_HEAD(&vcpu->async_pf.queue);
69         spin_lock_init(&vcpu->async_pf.lock);
70 }
71
72 static void async_pf_execute(struct work_struct *work)
73 {
74         struct kvm_async_pf *apf =
75                 container_of(work, struct kvm_async_pf, work);
76         struct mm_struct *mm = apf->mm;
77         struct kvm_vcpu *vcpu = apf->vcpu;
78         unsigned long addr = apf->addr;
79         gva_t gva = apf->gva;
80
81         might_sleep();
82
83         down_read(&mm->mmap_sem);
84         get_user_pages(NULL, mm, addr, 1, 1, 0, NULL, NULL);
85         up_read(&mm->mmap_sem);
86         kvm_async_page_present_sync(vcpu, apf);
87
88         spin_lock(&vcpu->async_pf.lock);
89         list_add_tail(&apf->link, &vcpu->async_pf.done);
90         spin_unlock(&vcpu->async_pf.lock);
91
92         /*
93          * apf may be freed by kvm_check_async_pf_completion() after
94          * this point
95          */
96
97         trace_kvm_async_pf_completed(addr, gva);
98
99         if (waitqueue_active(&vcpu->wq))
100                 wake_up_interruptible(&vcpu->wq);
101
102         mmput(mm);
103         kvm_put_kvm(vcpu->kvm);
104 }
105
106 void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
107 {
108         /* cancel outstanding work queue item */
109         while (!list_empty(&vcpu->async_pf.queue)) {
110                 struct kvm_async_pf *work =
111                         list_entry(vcpu->async_pf.queue.next,
112                                    typeof(*work), queue);
113                 list_del(&work->queue);
114
115 #ifdef CONFIG_KVM_ASYNC_PF_SYNC
116                 flush_work(&work->work);
117 #else
118                 if (cancel_work_sync(&work->work)) {
119                         mmput(work->mm);
120                         kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */
121                         kmem_cache_free(async_pf_cache, work);
122                 }
123 #endif
124         }
125
126         spin_lock(&vcpu->async_pf.lock);
127         while (!list_empty(&vcpu->async_pf.done)) {
128                 struct kvm_async_pf *work =
129                         list_entry(vcpu->async_pf.done.next,
130                                    typeof(*work), link);
131                 list_del(&work->link);
132                 kmem_cache_free(async_pf_cache, work);
133         }
134         spin_unlock(&vcpu->async_pf.lock);
135
136         vcpu->async_pf.queued = 0;
137 }
138
139 void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
140 {
141         struct kvm_async_pf *work;
142
143         while (!list_empty_careful(&vcpu->async_pf.done) &&
144               kvm_arch_can_inject_async_page_present(vcpu)) {
145                 spin_lock(&vcpu->async_pf.lock);
146                 work = list_first_entry(&vcpu->async_pf.done, typeof(*work),
147                                               link);
148                 list_del(&work->link);
149                 spin_unlock(&vcpu->async_pf.lock);
150
151                 kvm_arch_async_page_ready(vcpu, work);
152                 kvm_async_page_present_async(vcpu, work);
153
154                 list_del(&work->queue);
155                 vcpu->async_pf.queued--;
156                 kmem_cache_free(async_pf_cache, work);
157         }
158 }
159
160 int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
161                        struct kvm_arch_async_pf *arch)
162 {
163         struct kvm_async_pf *work;
164
165         if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
166                 return 0;
167
168         /* setup delayed work */
169
170         /*
171          * do alloc nowait since if we are going to sleep anyway we
172          * may as well sleep faulting in page
173          */
174         work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT);
175         if (!work)
176                 return 0;
177
178         work->wakeup_all = false;
179         work->vcpu = vcpu;
180         work->gva = gva;
181         work->addr = hva;
182         work->arch = *arch;
183         work->mm = current->mm;
184         atomic_inc(&work->mm->mm_users);
185         kvm_get_kvm(work->vcpu->kvm);
186
187         /* this can't really happen otherwise gfn_to_pfn_async
188            would succeed */
189         if (unlikely(kvm_is_error_hva(work->addr)))
190                 goto retry_sync;
191
192         INIT_WORK(&work->work, async_pf_execute);
193         if (!schedule_work(&work->work))
194                 goto retry_sync;
195
196         list_add_tail(&work->queue, &vcpu->async_pf.queue);
197         vcpu->async_pf.queued++;
198         kvm_arch_async_page_not_present(vcpu, work);
199         return 1;
200 retry_sync:
201         kvm_put_kvm(work->vcpu->kvm);
202         mmput(work->mm);
203         kmem_cache_free(async_pf_cache, work);
204         return 0;
205 }
206
207 int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
208 {
209         struct kvm_async_pf *work;
210
211         if (!list_empty_careful(&vcpu->async_pf.done))
212                 return 0;
213
214         work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
215         if (!work)
216                 return -ENOMEM;
217
218         work->wakeup_all = true;
219         INIT_LIST_HEAD(&work->queue); /* for list_del to work */
220
221         spin_lock(&vcpu->async_pf.lock);
222         list_add_tail(&work->link, &vcpu->async_pf.done);
223         spin_unlock(&vcpu->async_pf.lock);
224
225         vcpu->async_pf.queued++;
226         return 0;
227 }